Orthodontists' and laypersons' perception of mandibular asymmetries

Objective: To analyze orthodontists' and laypersons' perceptions of facial asymmetries caused by mandibular changes. Methods: The faces of two patients, a man and a woman, were photographed in natural head position, and additional photographs were produced with progressive mandibular shifts of 2, 4 and 6 mm from maximum habitual intercuspation (MHI). Intraclass correlation coefficients (ICC) and weighted kappa coefficients were used to test method reproducibility. The differences in scores for mandibular positions between orthodontists and lay persons were examined using Friedman analysis. All statistical analyses were performed at 95% confidence interval. Results: Orthodontists only perceived shifts greater than 4 mm from MHI position (p<0.05), and laypersons had similar results when analyzing the woman's photographs. However, when examining the man's photographs, laypersons did not perceive any change in relation to MHI. (p>0.05). Although median scores assigned by orthodontists were, in general, lower than those of laypersons, this difference was only significant for the 6-mm shift in both patients. Conclusions: Orthodontists and laypersons evaluated mandibular asymmetries differently. Orthodontists tended to be more critical when asymmetries were more severe. The evaluation of facial asymmetries also varied according to what patient was being examined, particularly among lay examiners.